package com.leyou.common.utils;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.List;
import java.util.Map;

/**
 *
 */
public class JsonUtils {

    public static final ObjectMapper mapper = new ObjectMapper();

    private static final Logger logger = LoggerFactory.getLogger(JsonUtils.class);

    public static String toString(Object obj) {
        if (obj == null) {
            return null;
        }
        if (obj.getClass() == String.class) {
            return (String) obj;
        }
        try {
            return mapper.writeValueAsString(obj);
        } catch (JsonProcessingException e) {
            logger.error("json序列化出错：" + obj, e);
            return null;
        }
    }

    public static <T> T toBean(String json, Class<T> tClass) {
        try {
            return mapper.readValue(json, tClass);
        } catch (IOException e) {
            logger.error("json解析出错：" + json, e);
            return null;
        }
    }

    public static <E> List<E> toList(String json, Class<E> eClass) {
        try {
            return mapper.readValue(json, mapper.getTypeFactory().constructCollectionType(List.class, eClass));
        } catch (IOException e) {
            logger.error("json解析出错：" + json, e);
            return null;
        }
    }

    public static <K, V> Map<K, V> toMap(String json, Class<K> kClass, Class<V> vClass) {
        try {
            return mapper.readValue(json, mapper.getTypeFactory().constructMapType(Map.class, kClass, vClass));
        } catch (IOException e) {
            logger.error("json解析出错：" + json, e);
            return null;
        }
    }

    public static <T> T nativeRead(String json, TypeReference<T> type) {
        try {
            return mapper.readValue(json, type);
        } catch (IOException e) {
            logger.error("json解析出错：" + json, e);
            return null;
        }
    }
        /**
         * Json 反序列化，将字符串转为对象
         */
/**        @Data
        @AllArgsConstructor
        @NoArgsConstructor
        static class User {
            String name;
            Integer age;
        }
        public static void main(String[] args){
            User user = new User("jack", 21);
//            // toString
//            String json = toString(user);
//            System.out.println("json = " + json);
//
//            //反序列化
//            User user1 = toBean(json, User.class);
//            System.out.println("user1 = " + user1);

//              // toList
//            String json = "[20, 209, 4, 43]";
//            List<Integer> list = toList(json, Integer.class);
//            System.out.println("list = " + list);

//            // toMap
//            String json = "{\"name\": \"jack\", \"age\": \"11\"}";
//            Map<String, String> map = toMap(json, String.class, String.class);
//            System.out.println("map = " + map);

            String json = "[{\"name\": \"jack\", \"age\": \"11\"}, {\"name\": \"rose\", \"age\": \"22\"}]";
            // 不允许出现 Map<String, String>.class(字节码不能写泛型)
            List<Map<String, String>> maps = nativeRead(json, new TypeReference<List<Map<String, String>>>() {
            });
            for (Map<String, String> map : maps) {
                System.out.println("maps = " + maps);
            }
        }
*/




}
